2JZ-GTE Misfiring/Surging???

[Makaveli]

My Aristo had a heater coolant hose leak. So mechanic replaced the hose and said there was water by coils/spark plugs. It sort of made the car running better. But when I start it when it's cold, the engine struggles to idle and there is a lot of engine vibration. I dont get any engine error codes on the dash. I have bought 6 brand new coil packs and this still hasnt fixed the issue. My mechanic reckons it could be one of the sensors that faulty. Has anyone experienced anything like this? Possible causes?

Thanks,
Sergei

[Stott69]

Have you got a multimeter?
Can check sensor as in here:
http://www.turbosupras.com/pdfs/JZA80%2 ... 20(2JZ-GTE).pdf

[Crucible]

Did it get hot at all? where the plugs replaced with the coil packs?

[Looonie]

On my old 2JZ-GE the heater hose leaked and water was collecting down in the valley around #6 plug causing the exact same symptoms, have you checked down in the valley for water and cleaned/replaced the plugs, as well as the coil packs?

[Makaveli]

6 New Spark Plugs and 6 new OEM Coil Packs.

I guess it could be the Crank Angle Sensor. I will be taking it to dealer in a few weeks time to get it sorted. Seems to be never ending with my car. I haven't got a voltmeter.

[Mr Ree]

How are the igntion loom connections that attach to the coils?

[Makaveli]

They have been fixed. Old ones were broken.

[Makaveli]

When it's cold, it struggles to idle. There is a lot of vibration in the engine. Also even when you drive it sometimes there is difficulty in accelerating (increasing RPM) and then it suddenly takes off as normal.

[Stott69]

When was the fuel filter last done? If its ignition you would smell unburnt fuel

[Makaveli]

There is not much on my car that hasn't been replaced. New fuel filter a few weeks ago. I dont think its fuel related. Gut feeling its some sort of sensor related to ignition. So probably crank angle sensor.

[Mr Ree]

I know you said no fault codes appeared on the dash, but does that mean you have actually run a diagnostic check? If not, then try that and see if anything shows up.

I would also recommend checking the TPS is within spec as that can cause stumbling issues

[Crucible]

There is not much on my car that hasn't been replaced. New fuel filter a few weeks ago. I dont think its fuel related. Gut feeling its some sort of sensor related to ignition. So probably crank angle sensor.

So your quite sure its down on a cylinder and missfiring then. If it has new coil packs and plugs then yep that just leaves bad trigger to coil, a position sensor or ecu.

It had a coolant leak so it def didnt get hot then?? no?

If you brought the car to me and told me it only happened after the coolant leak I would start with base checks and carry out TK test to rule out possible hg leak. You also say it happens when cold. With my experiance some leaking headgaskets will wash cylinder with water when sitting and cause a miss on start up.

Running it from cold for no more than a minute and touching each exhaust pipe and seeing which one is cooler will give you an idea of which cylinder isnt working. maybe hard with factory twin setup though..

[Mr Ree]

As you say Edyn, its pretty hard to get near individual runners on the TT setup.

Could you disconnect an injector or coil wire to identify which one makes the least difference when its removed? Atleast that is easier to access etc

[Crucible]

As you say Edyn, its pretty hard to get near individual runners on the TT setup.

Could you disconnect an injector or coil wire to identify which one makes the least difference when its removed? Atleast that is easier to access etc

Yes, those are def other options to find a dead pot. Youre onto it mate.

[Makaveli]

According to JZS147 Forums, it could be a Coolant Temp Sensor. I had another coolant (top radiator hose this time lol) hose go on me today. I might get some Samco Hoses and do entire engine soon.

[Mr Ree]

Really? I thought that if the temp sensor was faulty, the car just ran in safe rich mode all the time as it doesnt realise it has warmed up.

Ive never heard of it causing missing, but that means nothing at all.

Do you have any friends with a 2JZ that you could borrow a sensor from to eliminate the possibilty?

Also, im guessing it is the sensor that goes to the ecu, not the one that goes to the gauge?

[Crucible]

whoops..double post

[Crucible]

+1

Mr Ree is right, faulty temp sensor wont cause a missfire. Ones ive replaced on subarus just make it run a bit richer.

According to JZS147 Forums, it could be a Coolant Temp Sensor. I had another coolant (top radiator hose this time lol) hose go on me today. I might get some Samco Hoses and do entire engine soon.

Why is it popping hoses? you still havent said if it got hot or not??? Have you done a comp test just to be certain youre not chasing your tail???

meh, trying to diagnose problems on the internet is like playing pool with a rope!

[Mr Ree]

A soggy rope at that

[Makaveli]

No it hasn't got hot. Why do hoses crack? Mainly due to the fact that car is 16 years old and done around 160,000km.Considering the fact that it doesn't show any error codes, it would be a mission to test every sensor to make sure its functioning as it should.